Communication of data between spaced-apart locations is a necessary aspect of modern society. Communication of data is required to effectuate many varied functions and services. And, many varied types of communication systems have been deployed and are available for use through which to effectuate such functions and services.
A communication system includes, at a minimum, a first communication station and a second communication station interconnected by way of a communication channel. The communication stations are positioned at the locations between which data is to be communicated. And, data to be communicated by one of the communication stations to the other is sent thereto by way of the communication channel. Some communication systems are multi-user communication systems that permit large numbers of users to communicate therethrough. Large numbers of users are able to effectuate different types of communication services through use of many different types of multi-user communication systems. As technological advancements permit, new types of multi-user, and other, communication systems have been developed and deployed. Some of the new types of communication systems permit more efficient effectuation of existing communication services. With the progression of additional technological advancements, new types of communication systems in which such technological advancements are deployed shall correspondingly likely be made available.
Advancements in digital communication techniques, and circuitry therefore used to implement such techniques, are amongst the technological advancements that have, for instance, been implemented in many new communication systems. The use of digital communication techniques provides several advantages. For instance, improved communication efficiencies are possible as a result of the use of digital communication techniques. When digital communication techniques are utilized, the data that is to be communicated is digitized, or otherwise converted, into digital form. Communication redundancies typically exhibited by the data, in analog form, are then removed from the data, once digitized.
By removing the communication redundancies, redundant data need not be communicated. And, as a result, the communication capacity of a digital communication system can be substantially increased relative to the communication capacity permitted in a corresponding analog communication system.
A radio communication system is an exemplary type of communication system. In a radio communication system, the communication channel that interconnects the communication stations is formed, at least in part, upon a radio link. That is to say, a communication path that extends between the communication stations of the radio communication system includes a part defined upon a radio link. The data that is communicated between the communication stations is communicated upon the communication channel, referred to as a radio channel, defined upon the radio link.
Various advantages are provided through use of a radio communication system. A radio communication system is, for example, generally deployed more economically than a wireline counterpart. The deployment costs associated with the installation of the network infrastructure of a radio communication system are generally less than the deployment costs associated with installation of the network infrastructure of a corresponding, wireline counterpart. So, for reasons associated with minimization of deployment costs, a radio communication system is sometimes preferred over a corresponding, wireline counterpart. Also, a radio communication system is implementable as a mobile communication system. A mobile communication system provides for communication mobility. And, communications in a mobile communication system are thereby possible, from and between, locations at which communications utilizing a conventional wireline communication system would be impractical. That is to say, communications with a communication station as it is moving is sometimes also possible in a mobile communication system.
A cellular communication system is a type of radio communication system that provides for voice and data communication services. In a cellular communication system, multiple access by significant numbers of users is permitted. Cellular communication systems are popularly utilized and have achieved high penetration levels in many areas. The network infrastructures of cellular communication systems have been deployed throughout significant geographical portions of populated areas of the world. And, successive generations of cellular communication systems have been deployed, sometimes overlayed upon common geographical areas. Successor-generation systems, intended to supplement and, eventually, to replace existing systems are undergoing deployment or are under development.
The first cellular systems that were commercially deployed generally utilize conventional analog communication techniques and use frequency-division, multiple-access communication schemes. These systems are sometimes referred to as being first-generation (1G) cellular communication systems. And, first-generation systems generally provide for circuit-switched, voice communications.
Systems introduced, subsequent to the deployment of first-generation systems, and that first utilized digital communication techniques, are referred to as being second-generation (2G) cellular communication systems. These systems generally provide for some data services. And, 2.5G (second-and-a-half generation) and 3G (third-generation) systems are currently undergoing deployment. These systems, generally, provide for more extensive data services. That is to say, these systems generally provide for communication services at higher data rates as well as services effectuable at multiple data rates. And, successor-generation systems are being developed. When deployed, these systems shall likely provide opportunity for even more extensive data services.
A cellular communication system, referred to as a GSM (Global System for Mobile communications) cellular communication system, is exemplary of a second-generation cellular communication system. The GSM system operates pursuant to the protocols and standards set forth in an operational specification promulgated by the ETSI (European Telecommunications Standards Institute). The GSM system defines a communication scheme that utilizes a combination of frequency division multiple access (FDMA) and time-division multiple-access (TDMA) communication schemes. Networks constructed to be operable pursuant to the GSM operating specification have been installed throughout many areas. Many users subscribe to service in a GSM system to communicate telephonically therethrough. Similarly, other cellular communication systems, operable pursuant to other operating specifications have also been constructed throughout many areas. And, many other users subscribe to service in such other systems. The mobile nodes are of physical dimensions that permit the subscribers to hand-carry the mobile nodes. Mobile nodes are typically constructed to mimic operation of conventional telephonic stations. That is, mobile nodes typically are operable both to originate and to terminate telephonic calls in manners that correspond, at least from the perspective of the user thereof, to the manners by which conventional, telephonic stations are utilized to originate and to terminate such calls.
Calls can be placed to, or originated at, the mobile nodes for termination at the mobile node. Signaling is generated with the mobile node during a call set-up procedure as part of the call placement. And, pursuant to the call set-up procedure, an alert, such as a ringing tone, is caused to be generated at the mobile node. The alert alerts the user of the mobile node of the call placed thereto. And, the user of the mobile node is able to accept the call responsive to the alert. The call is accepted in a manner analogous to the manner by which the user of a conventional wireline station takes the wireline station off-hook.
When a call is placed at the mobile node, the call is referred to as being originated at the mobile node. To originate the call, the user enters the dialing digits that identify the station, i.e., the called party, to which the call is intended to be placed, i.e., terminated. Again, the call is placed in a manner analogous to the manner by which the dialing digits associated with the called party are entered at a conventional wireline station. Call signaling procedures are performed to ‘set-up’ the call. Such call signaling procedures are generally transparent to the user.
In some areas, certain designated service centers are designated by shortened codes. That is to say, shortened dialing codes, herein sometimes referred to as short numbers or short dialing codes, identify the certain designated service centers. For instance, in the United States, some areas have 9-1-1, emergency service centers. And, the 9-1-1 code is sometimes referred to as an emergency number. A person placing a request, e.g., for emergency assistance, enters the 9-1-1 code at a telephonic station. The call is routed, as a result, to an appropriate 9-1-1 service center. The 9-1-1 service center includes facilities that assist in quick response to the request. In other areas, other codes are used to identify such a service center. For instance, in the United Kingdom, an emergency services center is accessed telephonically from a telephonic station through the entry of a 9-9-9 code.
Some other service centers are analogously also designated by short numbers. For instance, directory service centers are accessed telephonically in some areas of the United States by entry of a 4-1-1 code at a telephonic station. In some other areas, such as parts of the United Kingdom, a directory service center is accessed telephonically by entry of a 1-9-2 code. Similarly, operator assistance is accessed telephonically in some areas by entry of the digit ‘0’ and, in some other areas, by entry of the short code 1-0-0.
Problems sometimes result when a mobile node is used through which to enter the short dialing codes. For instance, the mobile node might be positioned in an area at which a short code that designates a particular service center-type be of a first set, or sequence, of digits, and the mobile node might later be positioned in an area at which the short code that designates the particular service center-type be of a different set, or sequence, of digits. For example, the mobile node might initially be positioned in an area at which the short code associated with an emergency services center comprise the 9-1-1 digits. And, later the mobile node might be repositioned, to be located in an area at which the short code associated with the emergency service center comprises the 9-9-9 sequence of digits.
The home network associated with the mobile node, generally the network with which the user of the mobile node is familiar, therefore, might well use short codes that differ with the short codes that are used by the network in which the mobile node is subsequently positioned
The short codes with which the user is familiar or those that are stored, such as for speed-dialing purposes, at the mobile node might well differ with the codes that are required to effectuate a call to the intended service center. If the short code associated with a service center that the user of the mobile node intends to call is entered at a location that utilizes a different short code to access the service center, the intended service center is not accessed.
A manner is needed, therefore, by which better to provide for placement of a call from a mobile node to a service center using a short code. That is to say, a manner is needed by which to take into account the mobility inherent of a mobile node so that a service center that is accessed by entry of a short code by a user of the mobile node remains accessible irrespective of the position of the mobile node when a call is placed to the service center.
It is in light of this background information related to communications in a radio communication system that the significant improvements of the present invention have evolved.